The present invention relates to a composite wood product and a method and apparatus for manufacturing such a product. More particularly, a wood product is provided that is formed from layers of split and disrupted pieces of raw material such as small diameter tree branches and the like. The product is useful in making thick plates, pillar beams and the like for furniture, residential and commercial buildings and other structural objects.
In the past, ligneous group structural wood for use, e.g., for pillars and/or beams has generally included lumber, i.e., raw wood cut to a predetermined size and shape. The raw wood was normally formed of wood having a diameter of more than 100 mm yielding, from a standing tree main body, 50-60% and yielding, from a standing tree including branches as well, approximately 30-50% of the total tree material. Moreover, where the lumber includes defects such as gnarls, the strength of the lumber decreases remarkably relative to the strength inherent in wood without gnarls. In particular, the strength of the lumber having gnarls decreases 40-50% relative to that having no gnarls.
In a previously developed process, sometimes referred to as the "collected wood" process, raw wood was sawed into "plates" and adhered together in a pile to form a laminate. This was previously developed for solving the reduced strength problem caused by gnarls associated with lumber. This process improves the strength of the lumber by 60 to 75% compared to that having gnarls. However, a problem arises with this method in that the wooden parts are consumed by a cutting process for forming plate materials, whereby the yield from the standing tree is decreased to approximately 30-40% of the total tree material.
In another method involving single plate piled wood (LVL), wood is piled and adhered with a single plate (veneer). This process improves the yield from a standing tree to 60-70%. Since sawing is not required as with the normal lumbering process for forming the single plate, sawdust is not produced as in the lumbering and collected wood processes. Also, the strength achieved is similar to that obtained using the collected wood process. However, since the single plate is manufactured by rotating raw wood and peeling thin pieces off using a cutter, the matter which can be utilized is limited to raw wood of a relatively large diameter.
As is well known, wood and bamboo have many advantages including a desired look and feel, plentiful supply and easy processing, and quick reproduction. Thus, both have been widely used for many years. However, corresponding with an increase in the world's population and lengthening of lifespan, a remarkable increase in the need for wood and the like along with a diversification of uses has occurred, thereby increasing the demand for wood material to a new high. To this end, in addition to conventional lumber, new wood group materials of the collected wood and single plate piled wood (plywood, LVL) and the like have been developed as aforementioned.
However, despite the availability of conventional lumber, collected wood, and single plate piled wood (plywood, LVL), problems arise which prevent the effective use of limited forest resources. That is, conventional lumber and the collected wood process utilize less than one-half of a standing tree's volume. The single plate piled wood process can utilize 60-70% of the raw material wood volume, but the raw wood is limited to that which is extremely large in diameter. With today's shrinking of forest resources and a worsening of the global environment causing additional shrinkage of this resource, coupled with the widespread use of wood as a material for furniture, building and structural objects, it is no exaggeration to say that the realization of a wood manufacturing process for eliminating the waste of raw wood from big and small trees is urgently needed. The present invention provides a wood manufacturing process which solves this problem and others.